Allow command replay by hitting <enter>

command/command.go

@@ -23,12 +23,22 @@ func (c *Commands) Register(cmdstr string, cf cmdfunc) {
 	c.cmds[cmdstr] = cf
 }
 
+// Find will look up the command function for the given command input.
+// If it cannot find the command it will defualt to noCmdAvailable().
+// If the command is an empty string it will replay the last command.
 func (c *Commands) Find(cmdstr string) cmdfunc {
 	cmd, ok := c.cmds[cmdstr]
 	if !ok {
+		if cmdstr == "" {
+			return nullCommand
+		}
+
 		return noCmdAvailable
 	}
 
+	// Allow <enter> to replay last command
+	c.cmds[""] = cmd
+
 	return cmd
 }
 
@@ -40,3 +50,7 @@ func exitFunc() error {
 	os.Exit(0)
 	return nil
 }
+
+func nullCommand() error {
+	return nil
+}